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The surgery of intracranial vascular lesions provides special challenges for the anesthetist. The control of intracranial pressure, the prevention of cerebral aedema and the preservation of cerebral perfusion and oxygenation are leading requirements, to which are added measures to improve surgical access and to lower intravascular pressure in order to increase operability. Appropriate techniques and general provisions for meeting these requirements are discussed.

In 1969 INTERATOM received a contract from the Karlsruhe Nuclear Research Centre for the development, design and construction and start-up of an automatic lead-spectrometer facility for controlling the flow of fissile material at the product end of a LWR fuel-pin fabrication plant. The main features of the plant design are the application of pulsed-neutron active-interrogation technique with multi-isotope fissile-material assay capability, the adaptability to customers requirements, the design for heavy-duty operation and its simplicity and ease of operability. An on-line process-computer system coordinates and controls the sequence of the measurements, surveys the plant operation and is responsible for data acquisition and evaluation. The evaluation program, as organized, includes self-checking possibilities to detect malfunctioning of component parts. To minimize evaluation errors, this program is capable of differentiating between fuel pins with varying pellet column lengths and/or pins with varying enrichment as compared to a reference pin. Subsequent to the testing of the plant components, a continuous operation under field conditions was carried out. During this test, fulfilment of the specification, performance of the components, reproducibility, availability, safety and assay accuracy could be demonstrated. After a training period of four weeks, the operation of the plant was taken over by a technician.

The operation of nuclear reactors at elevated temperatures involving pressure- and temperature-cycling as well as corrosion and irradiation is associated with the gradual deterioration of the mechanical resistance of their critical components. The rate of deterioration depends not only on the intensity of the loading conditions and the level of the operating variables, but is sensitive to their sequence and interaction. The lack independence that is reflected by the development, under operating conditions, of creep and inelastic cyclic strain, as well by the deterioration of the strength properties accompanying such deformation (creep rupture, fatigue), introduces additional potential failure modes or conditions, consideration of which, in the reliability analysis, shifts the emphasis of this analysis from the catastrophic limiting states of failure under remote extremal conditions, of recurrence periods that are large multiples of the design (service) life of the structural element or system, to states of significant structural failure that seriously affect the operability of the reactor but are repairable, as well as to conditions of relatively minor structural failure of reactor elements during operation that are critical because they might lead to escape of contaminating fission products. After basic consideration of the formulation of structural reliability analysis and risk assessment for major structural failures in nuclear reactor plant systems, a review of the problems of design for creep and fatigue — with interaction between creep and fatigue effects — under reactor operational conditions is given.

The Bureau of Mines is developing a turbine driven by hot gases from burning coal. Primary emphasis so far has been to develop and test new blades designed to resist coal-ash erosion, the major problem confronting earlier developers of a coal-burning turbine. Improved coal preparation and feeding equipment and more efficient combustion and ash separation systems also are being developed. Overall objective of the Bureau is to build and operate a machine to demonstrate the technical feasibility of an open-cycle coal-burning gas turbine power plant. In the early phases of the Bureau turbine program, tests were conducted with a machine initially built by the Locomotive Development Committee of Bituminous Coal Research, Inc. Blade erosion had been revealed as the major problem in the LDC work, so prior to initial operations a gas turbine manufacturer was asked to review the results of the previous tests and recommend a new blade design. Several important changes were recommended, and a set of blades incorporating the new features was designed, fabricated, and installed in the turbine in 1963. The initial test of the turbine was conducted late in 1963. In 878 cumulative hr of operation the blades suffered little from erosion. The rotor blades appear capable of an additional operating period of up to 10,000 hr, and the stator blades (slightly notched at the bases on the last three rows) for at least 5000 hr. The test results indicated that with further research and development blades capable of the 50,000 to 100,000 hr regarded as minimum for commercial power plants are a definite possibility. The major difficulty in the 878-hr test was ash deposition on the blades, especially the first-stage stator blades. Means of preventing or controlling ash deposition are being sought during a second 1000-hr test of the new blades in the summer and fall of 1964. Certain modifications were made in the coal-combustion, ash-separation, and coal-feeding systems prior to this test to improve operability of the turbine plant.

In recent years surgical closure of defects in the ventricular septum has become a beneficial and relatively safe procedure. This increase in the scope of cardiac surgery demands specificity not only in establishing an accurate anatomic diagnosis but also in evaluating the associated hemodynamic alterations. One must be able to predict whether surgical closure of the anatomic defect will result in improvement or deterioration of the cardiac status. There appears to be no unanimity of opinion among thoracic surgeons in regard to the criteria of operability for patients with ventricular septal defects and severe pulmonary hypertension. At the Mayo Clinic the decision as to operability has become increasingly dependent on the magnitude of the pulmonary artery flow, which is considered to be a reflection of the degree of resistance in the pulmonary vascular bed (3). It was the purpose of the study to be reported here to evaluate the role of conventional roentgen methods in estimating this flow in the presence...

The development, progress, and sea experience of marine gas turbines in the U. S. Navy are reviewed. Practical problems encountered with engine components, installation arrangements, forward area support, and the marine environment are outlined. Development programs in progress with simple and regenerative open-cycle engines are presented. Development efforts of the future are postulated. Shipbuilding programs involving gas turbines are described. Gas turbines are now being considered for naval service over a wide range of power (40–25,000 hp per engine); the gas turbine should be further developed to meet projected needs; it, like any other prime mover, is to be treated as a component of an overall ship system and judged on the basis of lifetime cost, system reliability, maintainability, operability, performance, and personnel requirements. The authors suggest that specific weight and fuel rate, although significant features of any power source, have been overemphasized in the transfer of gas-turbine technology from aircraft to general marine use.

This paper describes how a host of sensors sensitive to X rays, ultraviolet and infrared, and to other electric or magnetic fields are distributed throughout a complex electronic system in such a manner that the system is continuously monitored to determine its condition of operability. The large quantity of data derived from these sensors are scanned by television techniques in order to meet the needs of rapid and automatic test. The test results are displayed on a cathode-ray tube in cyclogram fashion so that departures from normal operation may be easily and rapidly detected.

Solid state circuits demonstrating fast speed of response, miniaturization, and low power consumption have been replacing relay circuits in the logic portion of recent nuclear reactor safety systems. Some of the advantages of relay logic, such as circuit isolation, minimum number of parts, and low cost have been lost in the transition. A solid state and a relay safety system are described, and the application and merits of each are developed. Both system designs can meet the principal safety criterion of having the capability to take safety action when required under all operating conditions and with the presence of any one fault eitherwithin or outside the safety system. Secondary criteria used to compare the merits of each system are operability (freedom from false shutdowns), simplicity in testing, ease of maintenance, speed of response and cost. Reliability considerations include mode of component failure, frequency of testing, and the need for developmental testing.

1. By calculation and experimental verification, it has been found that there are sharp deformations of the temperature fields in the vicinities of regimes corresponding to the cut points between the limiting components, with the formation of regions with regimes of maximum purity (RMP regions). 2. In the design of towers for sharp fractionation of multicomponent mixtures, it is necessary to design for a certain reasonable excess number of trays in each section, to permit the formation of a sufficiently broad RMP region that can be placed under automatic control to ensure clean separation of the mixture into distillate and residue at the desired cut point. 3. It has been shown that, by using the properties of the RMP regions, it is possible to design an automatic control system that will give sharp fractionation at a given cut point. 4. Commercial tests of such an automatic control system have confirmed its operability and effectiveness.

A detailed review of eleven cases is presented in which the diagnosis of prostatic carcinoma, in terms of operability, was either over- or underestimated. The encouraging results, with regard to mortality, morbidity, and over-all survival, with an aggressive surgical approach for this disease are emphasized.

Inter operability among defense information systems is one of the most Important technologies in the modern information and electronic wars....

In this paper the performance of various simple systems of components in series and in parallel has been examined in terms of the performance of the individual components. The particular concepts considered are reliability and operability, the first being defined as the probability that a component (or system) will operate at all, and the second describing the operation of a component (or system) with respect to a particular variable. The general system examined is that of mn components arranged as n sets, of m parallel components, connected in series. Several assumptions are made as to the parameters of the systems, and the reliability and operability functions, for various values of m and n have been calculated and are presented in tabular or graphic form. Reliability is reduced by reducing n and increased by increasing m (a useful limit to m is three, even when n is quite large). Adding components in series will shift the operability distribution to the right, whereas adding them in parallel will shift the distribution to the left. In both cases the spread (or dispersion) is reduced, although skewness may be introduced.

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It has been shown that the adiabatic compressibility for organosilicon fluids is higher than for mineral oils that are used as dispersion media in the manufacture of greases.

In designing simulators we encounter the problem of the effect, on the simulation accuracy, of the deviation of the parameters of the simulating system from the rated values. A related problem is the estimation of the sensitivity and operability of control systems [1, 7].

The problem of the transmission of power over a transmission line from an alternating current generator at one end to a synchronous motor at the other is easily solved when the line is uniform or made up of a small number of uniform line segments. The object of the present note is to apply the theory of integral equations to the general case of the non-uniform line. The solution obtained for the current at any point on the line in the form of a rational function of the frequency of the two alternators is of advantage when resonance effects are being considered; the latter effects are hard to trace in the case of the uniform line by the usual methods. It seems probable that numerical methods and computing devices can be developed for the solution of the integral equations given. The effect of armature inductance on the power limit of the system may then be more easily studied than at present.

Similarities and differences among 22 methods of quantitatively predicting operator and technician performance are described. Emphasis has been given to eight methods most fully developed and most likely to be used by system engineers. Two general techniques are employed: analysis of historical data and computer-simulation of behavioral processes. No general purpose methodology is available; each method deals with some types of tasks and systems more efficiently than others. In general, simulation-based methods are more powerful than nonsimulation methods. Most methods output probability estimates of successful task/system performance and completion time, but are relatively insensitive to equipment design parameters, manpower selection and training needs. With only one exception no operability method utilizes a formal data base as input and in most cases the parameters these input data describe are not specifically indicated. For most methods validation and/or system application data are either lacking or incomplete.

In present practice, the decision as to whether a device has suffered damage as a result of exposure to a severe environment is generally based on operability during and after exposure, and visual inspection. Since these measures do not necessarily disclose the presence of mechanical faults, particularly in sealed units that are to see service, a need exists for a purely structural test to tell if a failure has occurred. Mechanical impedance techniques offer an opportunity for structural characterization to determine whether or not a device conforms to a predetermined standard or has suffered a change as a result of its history. From reference to network theory, it can be shown that changes in the resonant and antiresonant frequencies are sensitive indicators of change in a structure; these have the advantage of being relatively easy to measure with accuracy. The length of time that the structure must be excited in order to make the necessary measurements for such a test can be minimized by using random‐n...

HE application of methods developed in one discipline to the description or analysis of relationships in another has often proved rewarding in the past. The use of probability sampling by the social sciences, the widespread adoption of Stanley Hall's questionnaire techniques, and of course the almost universal appropriation of the classical experiment are cases in point. The present discussion is concerned with the possibility of applying a descriptive method recently developed in child development research to the study of development or of genetic-maturitysenescence cycles in a body politic, an economy, or in an entire cultural system. The first section will deal briefly with the conditions which fostered the method in its field of origin, the second section will describe the method, and the last part will outline its possible operability and utility in the fields of application.

The Pilgrim Nuclear Power Station is a 690 MWe General Electric designed Boiling Water Reactor. Pilgrim is located forty (40) miles south of Boston at Plymouth, Mssachusetts. It is situated on the Atlantic Seaboard (Cape Cod Bay) and uses circulating sea water for condensate cooling in the condenser. Pilgrim was granted a construction permit in August, 1968, achieved initial criticality in June, 1972 and began commercial operation in December, 1972. Bechtel Corporation was the prime contractor. For the first six (6) months of commercial operation, Pilgrim achieved a percent availability of 91.7 percent. I am pleased to report that generally speaking, the instrumentation and control system problems which developed during construction, startup and operation were of a routine nature. No outstanding problems arose requiring indepth re-evaluation and drastic design changes. The instrumentation and control systems have performed as expected. No false scrams have occurred which could be attributed to design deficiencies. Station Technical Specifications require that extensive routine testing on operating equipment be continuously performed to verify operability and locate and eliminate problems that could negate the required operability of said instrumentation when required. This paper discusses some of these Instrumnntation and Control System problems encountered and the solutions to these problems. This paper describes four (4) problems covering design and operating experience with the control and instrumentation systems for Pilgrim Nuclear Power Station Unit 1.

In the sick patient with mitral valve disease, surgery is unquestionably an important adjunct in our therapeutic armamentarium. The proper time for surgery can best be defined by correlating the clinical and hemodynamic features of the individual case with the life history of rheumatic valvular disease. Once embarked upon, the operation should be done in the manner which gives the best possible result with the least risk, always preserving the patient's valve when possible.

The February 1968 issue of Technometrics contained two papers in which the problem of maximising (or minimising) a function of several variables arose, where the values of the variables were subject to constraints. It is the purpose of this note to call attention to the use of transformations whereby certain forms of such constraints can be eliminated. The method was suggested by M. J. Box [1]. His paper does not seem to be well known to statisticians. It is hoped that what follows will serve to publicise this useful technique. With one exception, all the transformations in the present paper are given by Box. The paper by Hill, Hunter and Wichern [5] is an example of this situation in the context of the design of experiments. The constraints on the process variables time and temperature define a region of operability. The design problem is to find the maximum in this region of a function of the process variables called the design criterion. For one or two variables the maximum may easily be found by searching over a grid. For more variables, however, this process rapidly becomes inefficient. In an unconstrained problem recourse would be made to one of the well established hill climbing programmes such as that of Powell [8]. Use of such a procedure when constraints are present may well result in the location of a maximum outside the region of operability. In such a situation the use of transformations may allow us to employ the power of the hill climbing technique whilst ensuring that the solution obtained does not violate any of the constraints. As the simplest example, suppose we have a variable xi which is required to be non negative. Then if we write xi = y2 , an unconstrained search over all values of y, is equivalent to a constrained search for xi . The next simplest problem arises in the design of experiments in regression situations. See, for example, Clark [2]. Here each variable is subject to the constraint -1 < xi < 1, and the design criterion is to maximise the value of the

The test results presented were obtained over a 9 month period at the Naval Electronics Laboratory Center at San Diego. The test objective was to assess the structural and other physical property characteristics of incoherent, plastic jacketed, glass fiber-optic cable types of current manufacture. Tests were conducted to evaluate the capabilities of these type products to sustain structural integrity and operability after subjection to test exposures simulating Naval shipboard environmental conditions. A total of 29 types of tests were performed utilizing over 200 fiber-optic cables. A major part of this task involved the development of diagnostic test techniques for the evaluation of the test induced cable property modifications. A final report detailing the fiber-optic cable performance obtained in this test program is available by writing to the Library, Naval Electronics Laboratory Center, San Diego, California 92152. The report is entitled "Fiber-Optic Cable Test Evaluation" and identified as NELC TR-1869.

A review of selected portions of the ARHCO waste tank farm monitoring methods and systems was made. Only preliminary evaluations were made as the study was carried out over a period of only ten days. The study was requested by the Operation Support Engineering Department of ARHCO and the objectives as developed were divided into four tasks. Briefly, these were: evaluation of the waste tank dry well monitoring and data processing systems; evaluation of the accuracy (and precision) of material balance calculations for transfers from one tank to another tank; evaluation of the capabilities of material balance techniques for the detection of leaks in evaporator bottoms loop systems; and evaluation of the general operability of liquid level instrument systems currently in use and alternatives to these systems. The objectives of these tasks are restated in more detail in each of the sections below. An overview of the entire Hanford radioactive waste program including a limited description of the physical equipment involved can be found in PWM-530, Hanford Radioactive Waste Management Plans. Additional efforts have been initiated to establish an overall R and D program to more fully evaluate these systems and other factors relative to the successful operation of themore » ARHCO tank farm system.« less